Merge branch 'tip/perf/core' of...

Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core

Pull tracing updates from Steve Rostedt.

This commit:

      tracing: Remove the extra 4 bytes of padding in events

changes the ABI. All involved parties seem to agree that it's safe to
do now, but the devil is in the details ...
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/Kconfig

@@ -76,6 +76,15 @@ config OPTPROBES
 	depends on KPROBES && HAVE_OPTPROBES
 	depends on !PREEMPT
 
+config KPROBES_ON_FTRACE
+	def_bool y
+	depends on KPROBES && HAVE_KPROBES_ON_FTRACE
+	depends on DYNAMIC_FTRACE_WITH_REGS
+	help
+	 If function tracer is enabled and the arch supports full
+	 passing of pt_regs to function tracing, then kprobes can
+	 optimize on top of function tracing.
+
 config UPROBES
 	bool "Transparent user-space probes (EXPERIMENTAL)"
 	depends on UPROBE_EVENT && PERF_EVENTS
@@ -158,6 +167,9 @@ config HAVE_KRETPROBES
 config HAVE_OPTPROBES
 	bool
 
+config HAVE_KPROBES_ON_FTRACE
+	bool
+
 config HAVE_NMI_WATCHDOG
 	bool
 #

arch/x86/Kconfig

@@ -40,10 +40,12 @@ config X86
 	select HAVE_DMA_CONTIGUOUS if !SWIOTLB
 	select HAVE_KRETPROBES
 	select HAVE_OPTPROBES
+	select HAVE_KPROBES_ON_FTRACE
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FENTRY if X86_64
 	select HAVE_C_RECORDMCOUNT
 	select HAVE_DYNAMIC_FTRACE
+	select HAVE_DYNAMIC_FTRACE_WITH_REGS
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_GRAPH_FP_TEST

arch/x86/include/asm/ftrace.h

@@ -44,7 +44,6 @@
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 #define ARCH_SUPPORTS_FTRACE_OPS 1
-#define ARCH_SUPPORTS_FTRACE_SAVE_REGS
 #endif
 
 #ifndef __ASSEMBLY__

arch/x86/kernel/Makefile

@@ -65,8 +65,7 @@ obj-$(CONFIG_X86_TSC)		+= trace_clock.o
 obj-$(CONFIG_KEXEC)		+= machine_kexec_$(BITS).o
 obj-$(CONFIG_KEXEC)		+= relocate_kernel_$(BITS).o crash.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump_$(BITS).o
-obj-$(CONFIG_KPROBES)		+= kprobes.o
-obj-$(CONFIG_OPTPROBES)		+= kprobes-opt.o
+obj-y				+= kprobes/
 obj-$(CONFIG_MODULES)		+= module.o
 obj-$(CONFIG_DOUBLEFAULT) 	+= doublefault_32.o
 obj-$(CONFIG_KGDB)		+= kgdb.o

arch/x86/kernel/kprobes/Makefile

+#
+# Makefile for kernel probes
+#
+
+obj-$(CONFIG_KPROBES)		+= core.o
+obj-$(CONFIG_OPTPROBES)		+= opt.o
+obj-$(CONFIG_KPROBES_ON_FTRACE)	+= ftrace.o

arch/x86/kernel/kprobes-common.h → arch/x86/kernel/kprobes/common.h

@@ -99,4 +99,15 @@ static inline unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsig
 	return addr;
 }
 #endif
+
+#ifdef CONFIG_KPROBES_ON_FTRACE
+extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+			   struct kprobe_ctlblk *kcb);
+#else
+static inline int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+				  struct kprobe_ctlblk *kcb)
+{
+	return 0;
+}
+#endif
 #endif

arch/x86/kernel/kprobes.c → arch/x86/kernel/kprobes/core.c

@@ -58,7 +58,7 @@
 #include <asm/insn.h>
 #include <asm/debugreg.h>
 
-#include "kprobes-common.h"
+#include "common.h"
 
 void jprobe_return_end(void);
 
@@ -117,7 +117,7 @@ static void __kprobes __synthesize_relative_insn(void *from, void *to, u8 op)
 	struct __arch_relative_insn {
 		u8 op;
 		s32 raddr;
-	} __attribute__((packed)) *insn;
+	} __packed *insn;
 
 	insn = (struct __arch_relative_insn *)from;
 	insn->raddr = (s32)((long)(to) - ((long)(from) + 5));
@@ -541,23 +541,6 @@ reenter_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb
 	return 1;
 }
 
-#ifdef KPROBES_CAN_USE_FTRACE
-static void __kprobes skip_singlestep(struct kprobe *p, struct pt_regs *regs,
-				      struct kprobe_ctlblk *kcb)
-{
-	/*
-	 * Emulate singlestep (and also recover regs->ip)
-	 * as if there is a 5byte nop
-	 */
-	regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
-	if (unlikely(p->post_handler)) {
-		kcb->kprobe_status = KPROBE_HIT_SSDONE;
-		p->post_handler(p, regs, 0);
-	}
-	__this_cpu_write(current_kprobe, NULL);
-}
-#endif
-
 /*
  * Interrupts are disabled on entry as trap3 is an interrupt gate and they
  * remain disabled throughout this function.
@@ -616,12 +599,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
 	} else if (kprobe_running()) {
 		p = __this_cpu_read(current_kprobe);
 		if (p->break_handler && p->break_handler(p, regs)) {
-#ifdef KPROBES_CAN_USE_FTRACE
-			if (kprobe_ftrace(p)) {
-				skip_singlestep(p, regs, kcb);
-				return 1;
-			}
-#endif
+			if (!skip_singlestep(p, regs, kcb))
 				setup_singlestep(p, regs, kcb, 0);
 			return 1;
 		}
@@ -1075,50 +1053,6 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 	return 0;
 }
 
-#ifdef KPROBES_CAN_USE_FTRACE
-/* Ftrace callback handler for kprobes */
-void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
-				     struct ftrace_ops *ops, struct pt_regs *regs)
-{
-	struct kprobe *p;
-	struct kprobe_ctlblk *kcb;
-	unsigned long flags;
-
-	/* Disable irq for emulating a breakpoint and avoiding preempt */
-	local_irq_save(flags);
-
-	p = get_kprobe((kprobe_opcode_t *)ip);
-	if (unlikely(!p) || kprobe_disabled(p))
-		goto end;
-
-	kcb = get_kprobe_ctlblk();
-	if (kprobe_running()) {
-		kprobes_inc_nmissed_count(p);
-	} else {
-		/* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
-		regs->ip = ip + sizeof(kprobe_opcode_t);
-
-		__this_cpu_write(current_kprobe, p);
-		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
-		if (!p->pre_handler || !p->pre_handler(p, regs))
-			skip_singlestep(p, regs, kcb);
-		/*
-		 * If pre_handler returns !0, it sets regs->ip and
-		 * resets current kprobe.
-		 */
-	}
-end:
-	local_irq_restore(flags);
-}
-
-int __kprobes arch_prepare_kprobe_ftrace(struct kprobe *p)
-{
-	p->ainsn.insn = NULL;
-	p->ainsn.boostable = -1;
-	return 0;
-}
-#endif
-
 int __init arch_init_kprobes(void)
 {
 	return arch_init_optprobes();

arch/x86/kernel/kprobes/ftrace.c

+/*
+ * Dynamic Ftrace based Kprobes Optimization
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) Hitachi Ltd., 2012
+ */
+#include <linux/kprobes.h>
+#include <linux/ptrace.h>
+#include <linux/hardirq.h>
+#include <linux/preempt.h>
+#include <linux/ftrace.h>
+
+#include "common.h"
+
+static int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+			     struct kprobe_ctlblk *kcb)
+{
+	/*
+	 * Emulate singlestep (and also recover regs->ip)
+	 * as if there is a 5byte nop
+	 */
+	regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
+	if (unlikely(p->post_handler)) {
+		kcb->kprobe_status = KPROBE_HIT_SSDONE;
+		p->post_handler(p, regs, 0);
+	}
+	__this_cpu_write(current_kprobe, NULL);
+	return 1;
+}
+
+int __kprobes skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+			      struct kprobe_ctlblk *kcb)
+{
+	if (kprobe_ftrace(p))
+		return __skip_singlestep(p, regs, kcb);
+	else
+		return 0;
+}
+
+/* Ftrace callback handler for kprobes */
+void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
+				     struct ftrace_ops *ops, struct pt_regs *regs)
+{
+	struct kprobe *p;
+	struct kprobe_ctlblk *kcb;
+	unsigned long flags;
+
+	/* Disable irq for emulating a breakpoint and avoiding preempt */
+	local_irq_save(flags);
+
+	p = get_kprobe((kprobe_opcode_t *)ip);
+	if (unlikely(!p) || kprobe_disabled(p))
+		goto end;
+
+	kcb = get_kprobe_ctlblk();
+	if (kprobe_running()) {
+		kprobes_inc_nmissed_count(p);
+	} else {
+		/* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
+		regs->ip = ip + sizeof(kprobe_opcode_t);
+
+		__this_cpu_write(current_kprobe, p);
+		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+		if (!p->pre_handler || !p->pre_handler(p, regs))
+			__skip_singlestep(p, regs, kcb);
+		/*
+		 * If pre_handler returns !0, it sets regs->ip and
+		 * resets current kprobe.
+		 */
+	}
+end:
+	local_irq_restore(flags);
+}
+
+int __kprobes arch_prepare_kprobe_ftrace(struct kprobe *p)
+{
+	p->ainsn.insn = NULL;
+	p->ainsn.boostable = -1;
+	return 0;
+}

arch/x86/kernel/kprobes-opt.c → arch/x86/kernel/kprobes/opt.c

@@ -37,7 +37,7 @@
 #include <asm/insn.h>
 #include <asm/debugreg.h>
 
-#include "kprobes-common.h"
+#include "common.h"
 
 unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsigned long addr)
 {

include/linux/ftrace.h

@@ -74,7 +74,7 @@ typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
  *            and passed to the callback. If this flag is set, but the
  *            architecture does not support passing regs
- *            (ARCH_SUPPORTS_FTRACE_SAVE_REGS is not defined), then the
+ *            (CONFIG_DYNAMIC_FTRACE_WITH_REGS is not defined), then the
  *            ftrace_ops will fail to register, unless the next flag
  *            is set.
  * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
@@ -418,7 +418,7 @@ void ftrace_modify_all_code(int command);
 #endif
 
 #ifndef FTRACE_REGS_ADDR
-#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 # define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
 #else
 # define FTRACE_REGS_ADDR FTRACE_ADDR
@@ -480,7 +480,7 @@ extern int ftrace_make_nop(struct module *mod,
  */
 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 
-#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 /**
  * ftrace_modify_call - convert from one addr to another (no nop)
  * @rec: the mcount call site record

include/linux/ftrace_event.h

@@ -49,7 +49,6 @@ struct trace_entry {
 	unsigned char		flags;
 	unsigned char		preempt_count;
 	int			pid;
-	int			padding;
 };
 
 #define FTRACE_MAX_EVENT						\
@@ -272,7 +271,7 @@ extern int trace_define_field(struct ftrace_event_call *call, const char *type,
 extern int trace_add_event_call(struct ftrace_event_call *call);
 extern void trace_remove_event_call(struct ftrace_event_call *call);
 
-#define is_signed_type(type)	(((type)(-1)) < 0)
+#define is_signed_type(type)	(((type)(-1)) < (type)0)
 
 int trace_set_clr_event(const char *system, const char *event, int set);
 

include/linux/hardirq.h

@@ -180,10 +180,10 @@ extern void irq_exit(void);
 
 #define nmi_enter()						\
 	do {							\
+		lockdep_off();					\
 		ftrace_nmi_enter();				\
 		BUG_ON(in_nmi());				\
 		add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET);	\
-		lockdep_off();					\
 		rcu_nmi_enter();				\
 		trace_hardirq_enter();				\
 	} while (0)
@@ -192,10 +192,10 @@ extern void irq_exit(void);
 	do {							\
 		trace_hardirq_exit();				\
 		rcu_nmi_exit();					\
-		lockdep_on();					\
 		BUG_ON(!in_nmi());				\
 		sub_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET);	\
 		ftrace_nmi_exit();				\
+		lockdep_on();					\
 	} while (0)
 
 #endif /* LINUX_HARDIRQ_H */

include/linux/kprobes.h

@@ -49,16 +49,6 @@
 #define KPROBE_REENTER		0x00000004
 #define KPROBE_HIT_SSDONE	0x00000008
 
-/*
- * If function tracer is enabled and the arch supports full
- * passing of pt_regs to function tracing, then kprobes can
- * optimize on top of function tracing.
- */
-#if defined(CONFIG_FUNCTION_TRACER) && defined(ARCH_SUPPORTS_FTRACE_SAVE_REGS) \
-	&& defined(ARCH_SUPPORTS_KPROBES_ON_FTRACE)
-# define KPROBES_CAN_USE_FTRACE
-#endif
-
 /* Attach to insert probes on any functions which should be ignored*/
 #define __kprobes	__attribute__((__section__(".kprobes.text")))
 
@@ -316,7 +306,7 @@ extern int proc_kprobes_optimization_handler(struct ctl_table *table,
 #endif
 
 #endif /* CONFIG_OPTPROBES */
-#ifdef KPROBES_CAN_USE_FTRACE
+#ifdef CONFIG_KPROBES_ON_FTRACE
 extern void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 				  struct ftrace_ops *ops, struct pt_regs *regs);
 extern int arch_prepare_kprobe_ftrace(struct kprobe *p);

kernel/kprobes.c

@@ -919,7 +919,7 @@ static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
 }
 #endif /* CONFIG_OPTPROBES */
 
-#ifdef KPROBES_CAN_USE_FTRACE
+#ifdef CONFIG_KPROBES_ON_FTRACE
 static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
 	.func = kprobe_ftrace_handler,
 	.flags = FTRACE_OPS_FL_SAVE_REGS,
@@ -964,7 +964,7 @@ static void __kprobes disarm_kprobe_ftrace(struct kprobe *p)
 			   (unsigned long)p->addr, 1, 0);
 	WARN(ret < 0, "Failed to disarm kprobe-ftrace at %p (%d)\n", p->addr, ret);
 }
-#else	/* !KPROBES_CAN_USE_FTRACE */
+#else	/* !CONFIG_KPROBES_ON_FTRACE */
 #define prepare_kprobe(p)	arch_prepare_kprobe(p)
 #define arm_kprobe_ftrace(p)	do {} while (0)
 #define disarm_kprobe_ftrace(p)	do {} while (0)
@@ -1414,12 +1414,12 @@ static __kprobes int check_kprobe_address_safe(struct kprobe *p,
 	 */
 	ftrace_addr = ftrace_location((unsigned long)p->addr);
 	if (ftrace_addr) {
-#ifdef KPROBES_CAN_USE_FTRACE
+#ifdef CONFIG_KPROBES_ON_FTRACE
 		/* Given address is not on the instruction boundary */
 		if ((unsigned long)p->addr != ftrace_addr)
 			return -EILSEQ;
 		p->flags |= KPROBE_FLAG_FTRACE;
-#else	/* !KPROBES_CAN_USE_FTRACE */
+#else	/* !CONFIG_KPROBES_ON_FTRACE */
 		return -EINVAL;
 #endif
 	}

kernel/trace/Kconfig

@@ -39,6 +39,9 @@ config HAVE_DYNAMIC_FTRACE
 	help
 	  See Documentation/trace/ftrace-design.txt
 
+config HAVE_DYNAMIC_FTRACE_WITH_REGS
+	bool
+
 config HAVE_FTRACE_MCOUNT_RECORD
 	bool
 	help
@@ -434,6 +437,11 @@ config DYNAMIC_FTRACE
 	  were made. If so, it runs stop_machine (stops all CPUS)
 	  and modifies the code to jump over the call to ftrace.
 
+config DYNAMIC_FTRACE_WITH_REGS
+	def_bool y
+	depends on DYNAMIC_FTRACE
+	depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
+
 config FUNCTION_PROFILER
 	bool "Kernel function profiler"
 	depends on FUNCTION_TRACER

kernel/trace/blktrace.c

@@ -147,7 +147,7 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
 		return;
 
 	local_irq_save(flags);
-	buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
+	buf = this_cpu_ptr(bt->msg_data);
 	va_start(args, fmt);
 	n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
 	va_end(args);

kernel/trace/ftrace.c

@@ -111,6 +111,26 @@ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
 #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
 #endif
 
+/*
+ * Traverse the ftrace_global_list, invoking all entries.  The reason that we
+ * can use rcu_dereference_raw() is that elements removed from this list
+ * are simply leaked, so there is no need to interact with a grace-period
+ * mechanism.  The rcu_dereference_raw() calls are needed to handle
+ * concurrent insertions into the ftrace_global_list.
+ *
+ * Silly Alpha and silly pointer-speculation compiler optimizations!
+ */
+#define do_for_each_ftrace_op(op, list)			\
+	op = rcu_dereference_raw(list);			\
+	do
+
+/*
+ * Optimized for just a single item in the list (as that is the normal case).
+ */
+#define while_for_each_ftrace_op(op)				\
+	while (likely(op = rcu_dereference_raw((op)->next)) &&	\
+	       unlikely((op) != &ftrace_list_end))
+
 /**
  * ftrace_nr_registered_ops - return number of ops registered
  *
@@ -132,29 +152,21 @@ int ftrace_nr_registered_ops(void)
 	return cnt;
 }
 
-/*
- * Traverse the ftrace_global_list, invoking all entries.  The reason that we
- * can use rcu_dereference_raw() is that elements removed from this list
- * are simply leaked, so there is no need to interact with a grace-period
- * mechanism.  The rcu_dereference_raw() calls are needed to handle
- * concurrent insertions into the ftrace_global_list.
- *
- * Silly Alpha and silly pointer-speculation compiler optimizations!
- */
 static void
 ftrace_global_list_func(unsigned long ip, unsigned long parent_ip,
 			struct ftrace_ops *op, struct pt_regs *regs)
 {
-	if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
+	int bit;
+
+	bit = trace_test_and_set_recursion(TRACE_GLOBAL_START, TRACE_GLOBAL_MAX);
+	if (bit < 0)
 		return;
 
-	trace_recursion_set(TRACE_GLOBAL_BIT);
-	op = rcu_dereference_raw(ftrace_global_list); /*see above*/
-	while (op != &ftrace_list_end) {
+	do_for_each_ftrace_op(op, ftrace_global_list) {
 		op->func(ip, parent_ip, op, regs);
-		op = rcu_dereference_raw(op->next); /*see above*/
-	};
-	trace_recursion_clear(TRACE_GLOBAL_BIT);
+	} while_for_each_ftrace_op(op);
+
+	trace_clear_recursion(bit);
 }
 
 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
@@ -221,10 +233,24 @@ static void update_global_ops(void)
 	 * registered callers.
 	 */
 	if (ftrace_global_list == &ftrace_list_end ||
-	    ftrace_global_list->next == &ftrace_list_end)
+	    ftrace_global_list->next == &ftrace_list_end) {
 		func = ftrace_global_list->func;
+		/*
+		 * As we are calling the function directly.
+		 * If it does not have recursion protection,
+		 * the function_trace_op needs to be updated
+		 * accordingly.
+		 */
+		if (ftrace_global_list->flags & FTRACE_OPS_FL_RECURSION_SAFE)
+			global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
 		else
+			global_ops.flags &= ~FTRACE_OPS_FL_RECURSION_SAFE;
+	} else {
 		func = ftrace_global_list_func;
+		/* The list has its own recursion protection. */
+		global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;
+	}
+
 
 	/* If we filter on pids, update to use the pid function */
 	if (!list_empty(&ftrace_pids)) {
@@ -337,7 +363,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
 	if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
 		return -EINVAL;
 
-#ifndef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 	/*
 	 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
 	 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
@@ -4090,14 +4116,11 @@ ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
 	 */
 	preempt_disable_notrace();
 	trace_recursion_set(TRACE_CONTROL_BIT);
-	op = rcu_dereference_raw(ftrace_control_list);
-	while (op != &ftrace_list_end) {
+	do_for_each_ftrace_op(op, ftrace_control_list) {
 		if (!ftrace_function_local_disabled(op) &&
 		    ftrace_ops_test(op, ip))
 			op->func(ip, parent_ip, op, regs);
-
-		op = rcu_dereference_raw(op->next);
-	};
+	} while_for_each_ftrace_op(op);
 	trace_recursion_clear(TRACE_CONTROL_BIT);
 	preempt_enable_notrace();
 }
@@ -4112,27 +4135,26 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 		       struct ftrace_ops *ignored, struct pt_regs *regs)
 {
 	struct ftrace_ops *op;
+	int bit;
 
 	if (function_trace_stop)
 		return;
 
-	if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
+	bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
+	if (bit < 0)
 		return;
 
-	trace_recursion_set(TRACE_INTERNAL_BIT);
 	/*
 	 * Some of the ops may be dynamically allocated,
 	 * they must be freed after a synchronize_sched().
 	 */
 	preempt_disable_notrace();
-	op = rcu_dereference_raw(ftrace_ops_list);
-	while (op != &ftrace_list_end) {
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
 		if (ftrace_ops_test(op, ip))
 			op->func(ip, parent_ip, op, regs);
-		op = rcu_dereference_raw(op->next);
-	};
+	} while_for_each_ftrace_op(op);
 	preempt_enable_notrace();
-	trace_recursion_clear(TRACE_INTERNAL_BIT);
+	trace_clear_recursion(bit);
 }
 
 /*
@@ -4143,8 +4165,8 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
  * Archs are to support both the regs and ftrace_ops at the same time.
  * If they support ftrace_ops, it is assumed they support regs.
  * If call backs want to use regs, they must either check for regs
- * being NULL, or ARCH_SUPPORTS_FTRACE_SAVE_REGS.
- * Note, ARCH_SUPPORT_SAVE_REGS expects a full regs to be saved.
+ * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
+ * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
  * An architecture can pass partial regs with ftrace_ops and still
  * set the ARCH_SUPPORT_FTARCE_OPS.
  */

kernel/trace/ring_buffer.c

@@ -3,8 +3,10 @@
  *
  * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
  */
+#include <linux/ftrace_event.h>
 #include <linux/ring_buffer.h>
 #include <linux/trace_clock.h>
+#include <linux/trace_seq.h>
 #include <linux/spinlock.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
@@ -21,7 +23,6 @@
 #include <linux/fs.h>
 
 #include <asm/local.h>
-#include "trace.h"
 
 static void update_pages_handler(struct work_struct *work);
 
@@ -2432,41 +2433,76 @@ rb_reserve_next_event(struct ring_buffer *buffer,
 
 #ifdef CONFIG_TRACING
 
-#define TRACE_RECURSIVE_DEPTH 16
+/*
+ * The lock and unlock are done within a preempt disable section.
+ * The current_context per_cpu variable can only be modified
+ * by the current task between lock and unlock. But it can
+ * be modified more than once via an interrupt. To pass this
+ * information from the lock to the unlock without having to
+ * access the 'in_interrupt()' functions again (which do show
+ * a bit of overhead in something as critical as function tracing,
+ * we use a bitmask trick.
+ *
+ *  bit 0 =  NMI context
+ *  bit 1 =  IRQ context
+ *  bit 2 =  SoftIRQ context
+ *  bit 3 =  normal context.
+ *
+ * This works because this is the order of contexts that can
+ * preempt other contexts. A SoftIRQ never preempts an IRQ
+ * context.
+ *
+ * When the context is determined, the corresponding bit is
+ * checked and set (if it was set, then a recursion of that context
+ * happened).
+ *
+ * On unlock, we need to clear this bit. To do so, just subtract
+ * 1 from the current_context and AND it to itself.
+ *
+ * (binary)
+ *  101 - 1 = 100
+ *  101 & 100 = 100 (clearing bit zero)
+ *
+ *  1010 - 1 = 1001
+ *  1010 & 1001 = 1000 (clearing bit 1)
+ *
+ * The least significant bit can be cleared this way, and it
+ * just so happens that it is the same bit corresponding to
+ * the current context.
+ */
+static DEFINE_PER_CPU(unsigned int, current_context);
 
-/* Keep this code out of the fast path cache */
-static noinline void trace_recursive_fail(void)
+static __always_inline int trace_recursive_lock(void)
 {
-	/* Disable all tracing before we do anything else */
-	tracing_off_permanent();
+	unsigned int val = this_cpu_read(current_context);
+	int bit;
 
-	printk_once(KERN_WARNING "Tracing recursion: depth[%ld]:"
-		    "HC[%lu]:SC[%lu]:NMI[%lu]\n",
-		    trace_recursion_buffer(),
-		    hardirq_count() >> HARDIRQ_SHIFT,
-		    softirq_count() >> SOFTIRQ_SHIFT,
-		    in_nmi());
+	if (in_interrupt()) {
+		if (in_nmi())
+			bit = 0;
+		else if (in_irq())
+			bit = 1;
+		else
+			bit = 2;
+	} else
+		bit = 3;
 
-	WARN_ON_ONCE(1);
-}
+	if (unlikely(val & (1 << bit)))
+		return 1;
 
-static inline int trace_recursive_lock(void)
-{
-	trace_recursion_inc();
+	val |= (1 << bit);
+	this_cpu_write(current_context, val);
 
-	if (likely(trace_recursion_buffer() < TRACE_RECURSIVE_DEPTH))
 	return 0;
-
-	trace_recursive_fail();
-
-	return -1;
 }
 
-static inline void trace_recursive_unlock(void)
+static __always_inline void trace_recursive_unlock(void)
 {
-	WARN_ON_ONCE(!trace_recursion_buffer());
+	unsigned int val = this_cpu_read(current_context);
 
-	trace_recursion_dec();
+	val--;
+	val &= this_cpu_read(current_context);
+	this_cpu_write(current_context, val);
 }
 
 #else
@@ -3425,7 +3461,7 @@ static void rb_advance_iter(struct ring_buffer_iter *iter)
 	/* check for end of page padding */
 	if ((iter->head >= rb_page_size(iter->head_page)) &&
 	    (iter->head_page != cpu_buffer->commit_page))
-		rb_advance_iter(iter);
+		rb_inc_iter(iter);
 }
 
 static int rb_lost_events(struct ring_buffer_per_cpu *cpu_buffer)

kernel/trace/trace.c

@@ -709,10 +709,14 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 		return;
 
 	WARN_ON_ONCE(!irqs_disabled());
-	if (!current_trace->use_max_tr) {
-		WARN_ON_ONCE(1);
+
+	/* If we disabled the tracer, stop now */
+	if (current_trace == &nop_trace)
 		return;
-	}
+
+	if (WARN_ON_ONCE(!current_trace->use_max_tr))
+		return;
+
 	arch_spin_lock(&ftrace_max_lock);
 
 	tr->buffer = max_tr.buffer;
@@ -922,6 +926,9 @@ void tracing_reset(struct trace_array *tr, int cpu)
 {
 	struct ring_buffer *buffer = tr->buffer;
 
+	if (!buffer)
+		return;
+
 	ring_buffer_record_disable(buffer);
 
 	/* Make sure all commits have finished */
@@ -936,6 +943,9 @@ void tracing_reset_online_cpus(struct trace_array *tr)
 	struct ring_buffer *buffer = tr->buffer;
 	int cpu;
 
+	if (!buffer)
+		return;
+
 	ring_buffer_record_disable(buffer);
 
 	/* Make sure all commits have finished */
@@ -1167,7 +1177,6 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
 
 	entry->preempt_count		= pc & 0xff;
 	entry->pid			= (tsk) ? tsk->pid : 0;
-	entry->padding			= 0;
 	entry->flags =
 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
 		(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
@@ -1517,7 +1526,6 @@ static struct trace_buffer_struct *trace_percpu_nmi_buffer;
 static char *get_trace_buf(void)
 {
 	struct trace_buffer_struct *percpu_buffer;
-	struct trace_buffer_struct *buffer;
 
 	/*
 	 * If we have allocated per cpu buffers, then we do not
@@ -1535,9 +1543,7 @@ static char *get_trace_buf(void)
 	if (!percpu_buffer)
 		return NULL;
 
-	buffer = per_cpu_ptr(percpu_buffer, smp_processor_id());
-
-	return buffer->buffer;
+	return this_cpu_ptr(&percpu_buffer->buffer[0]);
 }
 
 static int alloc_percpu_trace_buffer(void)
@@ -3183,6 +3189,7 @@ static int tracing_set_tracer(const char *buf)
 	static struct trace_option_dentry *topts;
 	struct trace_array *tr = &global_trace;
 	struct tracer *t;
+	bool had_max_tr;
 	int ret = 0;
 
 	mutex_lock(&trace_types_lock);
@@ -3209,7 +3216,19 @@ static int tracing_set_tracer(const char *buf)
 	trace_branch_disable();
 	if (current_trace && current_trace->reset)
 		current_trace->reset(tr);
-	if (current_trace && current_trace->use_max_tr) {
+
+	had_max_tr = current_trace && current_trace->use_max_tr;
+	current_trace = &nop_trace;
+
+	if (had_max_tr && !t->use_max_tr) {
+		/*
+		 * We need to make sure that the update_max_tr sees that
+		 * current_trace changed to nop_trace to keep it from
+		 * swapping the buffers after we resize it.
+		 * The update_max_tr is called from interrupts disabled
+		 * so a synchronized_sched() is sufficient.
+		 */
+		synchronize_sched();
 		/*
 		 * We don't free the ring buffer. instead, resize it because
 		 * The max_tr ring buffer has some state (e.g. ring->clock) and
@@ -3220,10 +3239,8 @@ static int tracing_set_tracer(const char *buf)
 	}
 	destroy_trace_option_files(topts);
 
-	current_trace = &nop_trace;
-
 	topts = create_trace_option_files(t);
-	if (t->use_max_tr) {
+	if (t->use_max_tr && !had_max_tr) {
 		/* we need to make per cpu buffer sizes equivalent */
 		ret = resize_buffer_duplicate_size(&max_tr, &global_trace,
 						   RING_BUFFER_ALL_CPUS);
@@ -4037,7 +4054,6 @@ static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
 	 * Reset the buffer so that it doesn't have incomparable timestamps.
 	 */
 	tracing_reset_online_cpus(&global_trace);
-	if (max_tr.buffer)
 	tracing_reset_online_cpus(&max_tr);
 
 	mutex_unlock(&trace_types_lock);

kernel/trace/trace.h

@@ -291,16 +291,57 @@ struct tracer {
 
 
 /* Only current can touch trace_recursion */
-#define trace_recursion_inc() do { (current)->trace_recursion++; } while (0)
-#define trace_recursion_dec() do { (current)->trace_recursion--; } while (0)
 
-/* Ring buffer has the 10 LSB bits to count */
-#define trace_recursion_buffer() ((current)->trace_recursion & 0x3ff)
-
-/* for function tracing recursion */
-#define TRACE_INTERNAL_BIT		(1<<11)
-#define TRACE_GLOBAL_BIT		(1<<12)
-#define TRACE_CONTROL_BIT		(1<<13)
+/*
+ * For function tracing recursion:
+ *  The order of these bits are important.
+ *
+ *  When function tracing occurs, the following steps are made:
+ *   If arch does not support a ftrace feature:
+ *    call internal function (uses INTERNAL bits) which calls...
+ *   If callback is registered to the "global" list, the list
+ *    function is called and recursion checks the GLOBAL bits.
+ *    then this function calls...
+ *   The function callback, which can use the FTRACE bits to
+ *    check for recursion.
+ *
+ * Now if the arch does not suppport a feature, and it calls
+ * the global list function which calls the ftrace callback
+ * all three of these steps will do a recursion protection.
+ * There's no reason to do one if the previous caller already
+ * did. The recursion that we are protecting against will
+ * go through the same steps again.
+ *
+ * To prevent the multiple recursion checks, if a recursion
+ * bit is set that is higher than the MAX bit of the current
+ * check, then we know that the check was made by the previous
+ * caller, and we can skip the current check.
+ */
+enum {
+	TRACE_BUFFER_BIT,
+	TRACE_BUFFER_NMI_BIT,
+	TRACE_BUFFER_IRQ_BIT,
+	TRACE_BUFFER_SIRQ_BIT,
+
+	/* Start of function recursion bits */
+	TRACE_FTRACE_BIT,
+	TRACE_FTRACE_NMI_BIT,
+	TRACE_FTRACE_IRQ_BIT,
+	TRACE_FTRACE_SIRQ_BIT,
+
+	/* GLOBAL_BITs must be greater than FTRACE_BITs */
+	TRACE_GLOBAL_BIT,
+	TRACE_GLOBAL_NMI_BIT,
+	TRACE_GLOBAL_IRQ_BIT,
+	TRACE_GLOBAL_SIRQ_BIT,
+
+	/* INTERNAL_BITs must be greater than GLOBAL_BITs */
+	TRACE_INTERNAL_BIT,
+	TRACE_INTERNAL_NMI_BIT,
+	TRACE_INTERNAL_IRQ_BIT,
+	TRACE_INTERNAL_SIRQ_BIT,
+
+	TRACE_CONTROL_BIT,
 
 /*
  * Abuse of the trace_recursion.
@@ -309,11 +350,77 @@ struct tracer {
  * was called in irq context but we have irq tracing off. Since this
  * can only be modified by current, we can reuse trace_recursion.
  */
-#define TRACE_IRQ_BIT			(1<<13)
+	TRACE_IRQ_BIT,
+};
+
+#define trace_recursion_set(bit)	do { (current)->trace_recursion |= (1<<(bit)); } while (0)
+#define trace_recursion_clear(bit)	do { (current)->trace_recursion &= ~(1<<(bit)); } while (0)
+#define trace_recursion_test(bit)	((current)->trace_recursion & (1<<(bit)))
+
+#define TRACE_CONTEXT_BITS	4
+
+#define TRACE_FTRACE_START	TRACE_FTRACE_BIT
+#define TRACE_FTRACE_MAX	((1 << (TRACE_FTRACE_START + TRACE_CONTEXT_BITS)) - 1)
+
+#define TRACE_GLOBAL_START	TRACE_GLOBAL_BIT
+#define TRACE_GLOBAL_MAX	((1 << (TRACE_GLOBAL_START + TRACE_CONTEXT_BITS)) - 1)
+
+#define TRACE_LIST_START	TRACE_INTERNAL_BIT
+#define TRACE_LIST_MAX		((1 << (TRACE_LIST_START + TRACE_CONTEXT_BITS)) - 1)
+
+#define TRACE_CONTEXT_MASK	TRACE_LIST_MAX
+
+static __always_inline int trace_get_context_bit(void)
+{
+	int bit;
+
+	if (in_interrupt()) {
+		if (in_nmi())
+			bit = 0;
 
-#define trace_recursion_set(bit)	do { (current)->trace_recursion |= (bit); } while (0)
-#define trace_recursion_clear(bit)	do { (current)->trace_recursion &= ~(bit); } while (0)
-#define trace_recursion_test(bit)	((current)->trace_recursion & (bit))
+		else if (in_irq())
+			bit = 1;
+		else
+			bit = 2;
+	} else
+		bit = 3;
+
+	return bit;
+}
+
+static __always_inline int trace_test_and_set_recursion(int start, int max)
+{
+	unsigned int val = current->trace_recursion;
+	int bit;
+
+	/* A previous recursion check was made */
+	if ((val & TRACE_CONTEXT_MASK) > max)
+		return 0;
+
+	bit = trace_get_context_bit() + start;
+	if (unlikely(val & (1 << bit)))
+		return -1;
+
+	val |= 1 << bit;
+	current->trace_recursion = val;
+	barrier();
+
+	return bit;
+}
+
+static __always_inline void trace_clear_recursion(int bit)
+{
+	unsigned int val = current->trace_recursion;
+
+	if (!bit)
+		return;
+
+	bit = 1 << bit;
+	val &= ~bit;
+
+	barrier();
+	current->trace_recursion = val;
+}
 
 #define TRACE_PIPE_ALL_CPU	-1
 

kernel/trace/trace_clock.c

@@ -21,8 +21,6 @@
 #include <linux/ktime.h>
 #include <linux/trace_clock.h>
 
-#include "trace.h"
-
 /*
  * trace_clock_local(): the simplest and least coherent tracing clock.
  *

kernel/trace/trace_events.c

@@ -116,7 +116,6 @@ static int trace_define_common_fields(void)
 	__common_field(unsigned char, flags);
 	__common_field(unsigned char, preempt_count);
 	__common_field(int, pid);
-	__common_field(int, padding);
 
 	return ret;
 }

kernel/trace/trace_functions.c

@@ -47,34 +47,6 @@ static void function_trace_start(struct trace_array *tr)
 	tracing_reset_online_cpus(tr);
 }
 
-static void
-function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip,
-				 struct ftrace_ops *op, struct pt_regs *pt_regs)
-{
-	struct trace_array *tr = func_trace;
-	struct trace_array_cpu *data;
-	unsigned long flags;
-	long disabled;
-	int cpu;
-	int pc;
-
-	if (unlikely(!ftrace_function_enabled))
-		return;
-
-	pc = preempt_count();
-	preempt_disable_notrace();
-	local_save_flags(flags);
-	cpu = raw_smp_processor_id();
-	data = tr->data[cpu];
-	disabled = atomic_inc_return(&data->disabled);
-
-	if (likely(disabled == 1))
-		trace_function(tr, ip, parent_ip, flags, pc);
-
-	atomic_dec(&data->disabled);
-	preempt_enable_notrace();
-}
-
 /* Our option */
 enum {
 	TRACE_FUNC_OPT_STACK	= 0x1,
@@ -85,34 +57,34 @@ static struct tracer_flags func_flags;
 static void
 function_trace_call(unsigned long ip, unsigned long parent_ip,
 		    struct ftrace_ops *op, struct pt_regs *pt_regs)
-
 {
 	struct trace_array *tr = func_trace;
 	struct trace_array_cpu *data;
 	unsigned long flags;
-	long disabled;
+	unsigned int bit;
 	int cpu;
 	int pc;
 
 	if (unlikely(!ftrace_function_enabled))
 		return;
 
-	/*
-	 * Need to use raw, since this must be called before the
-	 * recursive protection is performed.
-	 */
-	local_irq_save(flags);
-	cpu = raw_smp_processor_id();
-	data = tr->data[cpu];
-	disabled = atomic_inc_return(&data->disabled);
-
-	if (likely(disabled == 1)) {
 	pc = preempt_count();
+	preempt_disable_notrace();
+
+	bit = trace_test_and_set_recursion(TRACE_FTRACE_START, TRACE_FTRACE_MAX);
+	if (bit < 0)
+		goto out;
+
+	cpu = smp_processor_id();
+	data = tr->data[cpu];
+	if (!atomic_read(&data->disabled)) {
+		local_save_flags(flags);
 		trace_function(tr, ip, parent_ip, flags, pc);
 	}
+	trace_clear_recursion(bit);
 
-	atomic_dec(&data->disabled);
-	local_irq_restore(flags);
+ out:
+	preempt_enable_notrace();
 }
 
 static void
@@ -185,11 +157,6 @@ static void tracing_start_function_trace(void)
 {
 	ftrace_function_enabled = 0;
 
-	if (trace_flags & TRACE_ITER_PREEMPTONLY)
-		trace_ops.func = function_trace_call_preempt_only;
-	else
-		trace_ops.func = function_trace_call;
-
 	if (func_flags.val & TRACE_FUNC_OPT_STACK)
 		register_ftrace_function(&trace_stack_ops);
 	else

kernel/trace/trace_functions_graph.c

@@ -47,6 +47,8 @@ struct fgraph_data {
 #define TRACE_GRAPH_PRINT_ABS_TIME	0x20
 #define TRACE_GRAPH_PRINT_IRQS		0x40
 
+static unsigned int max_depth;
+
 static struct tracer_opt trace_opts[] = {
 	/* Display overruns? (for self-debug purpose) */
 	{ TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
@@ -250,8 +252,9 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
 		return 0;
 
 	/* trace it when it is-nested-in or is a function enabled. */
-	if (!(trace->depth || ftrace_graph_addr(trace->func)) ||
-	      ftrace_graph_ignore_irqs())
+	if ((!(trace->depth || ftrace_graph_addr(trace->func)) ||
+	     ftrace_graph_ignore_irqs()) ||
+	    (max_depth && trace->depth >= max_depth))
 		return 0;
 
 	local_irq_save(flags);
@@ -1457,6 +1460,59 @@ static struct tracer graph_trace __read_mostly = {
 #endif
 };
 
+
+static ssize_t
+graph_depth_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		  loff_t *ppos)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	max_depth = val;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+graph_depth_read(struct file *filp, char __user *ubuf, size_t cnt,
+		 loff_t *ppos)
+{
+	char buf[15]; /* More than enough to hold UINT_MAX + "\n"*/
+	int n;
+
+	n = sprintf(buf, "%d\n", max_depth);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
+}
+
+static const struct file_operations graph_depth_fops = {
+	.open		= tracing_open_generic,
+	.write		= graph_depth_write,
+	.read		= graph_depth_read,
+	.llseek		= generic_file_llseek,
+};
+
+static __init int init_graph_debugfs(void)
+{
+	struct dentry *d_tracer;
+
+	d_tracer = tracing_init_dentry();
+	if (!d_tracer)
+		return 0;
+
+	trace_create_file("max_graph_depth", 0644, d_tracer,
+			  NULL, &graph_depth_fops);
+
+	return 0;
+}
+fs_initcall(init_graph_debugfs);
+
 static __init int init_graph_trace(void)
 {
 	max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);

kernel/trace/trace_selftest.c

@@ -415,7 +415,8 @@ static void trace_selftest_test_recursion_func(unsigned long ip,
 	 * The ftrace infrastructure should provide the recursion
 	 * protection. If not, this will crash the kernel!
 	 */
-	trace_selftest_recursion_cnt++;
+	if (trace_selftest_recursion_cnt++ > 10)
+		return;
 	DYN_FTRACE_TEST_NAME();
 }
 
@@ -452,7 +453,6 @@ trace_selftest_function_recursion(void)
 	char *func_name;
 	int len;
 	int ret;
-	int cnt;
 
 	/* The previous test PASSED */
 	pr_cont("PASSED\n");
@@ -510,19 +510,10 @@ trace_selftest_function_recursion(void)
 
 	unregister_ftrace_function(&test_recsafe_probe);
 
-	/*
-	 * If arch supports all ftrace features, and no other task
-	 * was on the list, we should be fine.
-	 */
-	if (!ftrace_nr_registered_ops() && !FTRACE_FORCE_LIST_FUNC)
-		cnt = 2; /* Should have recursed */
-	else
-		cnt = 1;
-
 	ret = -1;
-	if (trace_selftest_recursion_cnt != cnt) {
-		pr_cont("*callback not called expected %d times (%d)* ",
-			cnt, trace_selftest_recursion_cnt);
+	if (trace_selftest_recursion_cnt != 2) {
+		pr_cont("*callback not called expected 2 times (%d)* ",
+			trace_selftest_recursion_cnt);
 		goto out;
 	}
 
@@ -568,7 +559,7 @@ trace_selftest_function_regs(void)
 	int ret;
 	int supported = 0;
 
-#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 	supported = 1;
 #endif
 

kernel/trace/trace_syscalls.c

@@ -77,7 +77,7 @@ static struct syscall_metadata *syscall_nr_to_meta(int nr)
 	return syscalls_metadata[nr];
 }
 
-enum print_line_t
+static enum print_line_t
 print_syscall_enter(struct trace_iterator *iter, int flags,
 		    struct trace_event *event)
 {
@@ -130,7 +130,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
 	return TRACE_TYPE_HANDLED;
 }
 
-enum print_line_t
+static enum print_line_t
 print_syscall_exit(struct trace_iterator *iter, int flags,
 		   struct trace_event *event)
 {
@@ -270,7 +270,7 @@ static int syscall_exit_define_fields(struct ftrace_event_call *call)
 	return ret;
 }
 
-void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
+static void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 {
 	struct syscall_trace_enter *entry;
 	struct syscall_metadata *sys_data;
@@ -305,7 +305,7 @@ void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 		trace_current_buffer_unlock_commit(buffer, event, 0, 0);
 }
 
-void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
+static void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 {
 	struct syscall_trace_exit *entry;
 	struct syscall_metadata *sys_data;
@@ -337,7 +337,7 @@ void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 		trace_current_buffer_unlock_commit(buffer, event, 0, 0);
 }
 
-int reg_event_syscall_enter(struct ftrace_event_call *call)
+static int reg_event_syscall_enter(struct ftrace_event_call *call)
 {
 	int ret = 0;
 	int num;
@@ -356,7 +356,7 @@ int reg_event_syscall_enter(struct ftrace_event_call *call)
 	return ret;
 }
 
-void unreg_event_syscall_enter(struct ftrace_event_call *call)
+static void unreg_event_syscall_enter(struct ftrace_event_call *call)
 {
 	int num;
 
@@ -371,7 +371,7 @@ void unreg_event_syscall_enter(struct ftrace_event_call *call)
 	mutex_unlock(&syscall_trace_lock);
 }
 
-int reg_event_syscall_exit(struct ftrace_event_call *call)
+static int reg_event_syscall_exit(struct ftrace_event_call *call)
 {
 	int ret = 0;
 	int num;
@@ -390,7 +390,7 @@ int reg_event_syscall_exit(struct ftrace_event_call *call)
 	return ret;
 }
 
-void unreg_event_syscall_exit(struct ftrace_event_call *call)
+static void unreg_event_syscall_exit(struct ftrace_event_call *call)
 {
 	int num;
 
@@ -459,7 +459,7 @@ unsigned long __init __weak arch_syscall_addr(int nr)
 	return (unsigned long)sys_call_table[nr];
 }
 
-int __init init_ftrace_syscalls(void)
+static int __init init_ftrace_syscalls(void)
 {
 	struct syscall_metadata *meta;
 	unsigned long addr;

kernel/trace/trace_uprobe.c

@@ -258,6 +258,10 @@ static int create_trace_uprobe(int argc, char **argv)
 		goto fail_address_parse;
 
 	inode = igrab(path.dentry->d_inode);
+	if (!S_ISREG(inode->i_mode)) {
+		ret = -EINVAL;
+		goto fail_address_parse;
+	}
 
 	argc -= 2;
 	argv += 2;
@@ -356,7 +360,7 @@ static int create_trace_uprobe(int argc, char **argv)
 	if (inode)
 		iput(inode);
 
-	pr_info("Failed to parse address.\n");
+	pr_info("Failed to parse address or file.\n");
 
 	return ret;
 }